DOWNHOLE ROD PUMP FOR EXTRACTION OF HIGH-VISCOSITY OIL Russian patent published in 2012 - IPC F04B47/00 

FIELD: engines and pumps.

SUBSTANCE: proposed pump comprises cylinder with seat communicated by its top with flow string. Plunger arranged in cylinder to make above-plunger chamber and communicated with flow string provided with thrust. Annular pressure valve with diameter exceeding plunger diameter is fixed on flow string between said thrust and plunger. Suction valve communicates above-plunger chamber with downhole space. Pressure well upstroke limiter is made up of ring fitted in flow string. Plunger is hollow. Suction valve is furnished with pusher rigidly coupled with flow string and fitted inside plunger to reciprocate therein. Reciprocation is limited by pusher outer ledge from above and by suction valve from below to shut off plunger chamber in down travel. Cylinder is provided with ring grooves to receive spring-loaded stroke limiter made integral with pressure valve provided with brake to interact with flow string at force not exceeding limiter ring.

EFFECT: higher reliability, simplified servicing and repair.

3 dwg